1. Technical Field
Exemplary aspects of this disclosure generally relate to a print head array unit and a method of manufacturing the print head array unit, and more particularly, to a print head array unit and a method of manufacturing the print head array unit, and an image forming apparatus that includes the print head array unit.
2. Description of the Background Art
There is known an image forming apparatus, such as a printer, a facsimile machine, a copier, and a multi-functional system including any combination thereof, that employs an ink jet recording device ejecting ink for recording in an image forming operation.
Such an ink jet recording device uses, for example, a recording head that ejects liquid droplets of ink.
In the image forming apparatus of this type, an image forming operation is conducted by the recording head ejecting ink droplets onto a recording medium, typically although not necessarily a sheet of paper. It is to be noted that the image forming operation mentioned herein refers to any operation by which an image is fixed in tangible form, whether by recording, printing, imaging, or some other process or combination of processes.
Such image forming apparatuses are generally classified into two types, a serial-type image forming apparatus and a line-type image forming apparatus.
The serial-type image forming apparatus performs the image forming operation by moving the recording head in a main scan direction while ejecting ink droplets onto a sheet of a recording medium.
By contrast, the line-type image forming apparatus uses a line-type recording head that performs the image forming operation by ejecting the ink droplets without moving the recording head, that is, by keeping the recording head stationary while moving the sheet of the recording medium. Both types have advantages and disadvantages.
In order to form a full-line head including a nozzle array, a length of which is similar or equal to a width of the recording sheet or a so-called long head having the nozzle array, the length of which is similar or equal to half the sheet width direction, there is known a technique in which a number of short heads are arranged in the sheet width direction.
For example, JP-2007-136254-A discloses a head unit in which a liquid droplet discharge head is secured to a head member retainer which is then adjustably mounted to a head holding plate.
Japanese Patent Number 3552522 discloses a method and a device for bonding and assembling of component using a holding member and an adhesive.
According to WO-04-022344, a plurality of ink jet heads is mounted to a position adjustment plate including reference holes, and then the position adjustment plate is mounted and fixed to a common mounting plate member including reference pins by fitting the reference holes of the position adjustment plate to the reference pins of the common plate member.
According to JP-2001-162892-A, a plurality of heads is arranged on a single sub-carriage so as to form a long head. A head portion image acquisition mechanism, a head portion image acquisition mechanism, and a sub-carriage moving mechanism are provided so as to detect the target positions for the heads in order to accurately arrange the plurality of the heads.
It is difficult to form the full-line head using a single head due to fabrication yield and the like. Therefore, in general, instead of using a long single head, a plurality of heads is arranged in a line to form the full-line head. This is a so-called “head array unit”.
In such a head array unit, a plurality of heads needs to be arranged accurately relative to a mounting member on which the plurality of heads is mounted and fixed.
However, as described in JP-2001-162892-A, when the plurality of heads is arranged on the single sub-carriage by optically detecting the target positions and then adjusting the position of the heads so as to form the long head, a larger assembly facility is needed, complicating accurate positioning of the plurality of the heads.
Furthermore, as described in WO-04-022344, when the plurality of the ink jet heads is mounted and fixed to the position adjustment plate including the reference holes and then the position adjustment plate is mounted and fixed to the common mounting plate member including the reference pins by fitting the reference holes to the reference pins of the common plate member, a number of reference pins need to be accurately provided to the common mounting plate member, thereby complicating the structure of the common mounting plate member and increasing the cost of the heads.